1. Field of the Invention
The invention is directed to a pipe connection.
2. Description of the Prior Art
A pipe connection of the generic type is manufactured by Geberit. In this system, a composite pipe, as it is called, is pushed onto a red-brass fitting. The composite pipe comprises an inner pipe with an aluminum jacket which conducts liquid and a sheathing pipe which is arranged over the inner pipe and serves for external protection. The inner pipe and the sheathing pipe are manufactured from plastic. The fitting has a region which extends in the longitudinal direction and which is provided with a stop, wherein the pipe to be connected is pushed on up to this stop. The region adjacent to the stop has two inner grooves, a sealing ring being arranged in each inner groove. The remaining portion is highly contoured, so that the pipe which is pushed on molds itself to the contour during pressing. After the pipe is pushed on, pressing tongs are applied externally and the pipe is pressed on in the area of the sealing ring as well as in the contoured area. In this case, the sealing ring area assumes the sealing function and the contoured area serve to axially secure the pipe and fitting. A disadvantage in this prior art system is that the composite pipe can be used only for a narrow range of temperature and pressure. Further, the manufacture of the fitting is complicated because the contoured end regions and the sealing ring region must be produced very precisely.
Another press connection system is manufactured by Deutsche ALWA GmbH. In this system for copper pipes and copper fittings, a continuous rubber collar is arranged in the interior of the fitting which is almost smoothly flush. In the center, the collar has a web or ridge which extends radially inward and serves as a stop for the pipes that are pushed in. A flanging or beading is provided on the inside around the front end regions of the fitting for fixing the inserted rubber collar axially. Two spaced beads are formed externally on the fitting by pressing tongs having a wide pressing jaw. This is carried out in such a way that the pushed in pipe is pressed in in this region. A disadvantage in this system consists in that the pressing jaw occupies extensive space, so that pressing is impossible in confined areas. Further, a lengthening is required for the majority of fittings, especially in the case of T-pieces, so that the pressing tongs can be applied.
A prior art reference DE 91 13 050 U1 discloses a connection for conduit or line pipes comprising a fitting having a connection piece. A protective sleeve covering the connection piece is detachably arranged on the fitting at a distance radially from the connection piece, and a composite pipe whose end area can be connected with the connection piece accompanied by radial plastic deformation. The connection piece has a sealing ring. In order to connect the end of the composite pipe with the connection piece, the protective sleeve is separated from the fitting and pushed back on the pipe until the end of the composite pipe can be pressed radially with pressing tongs accompanied by deformation. After pressing and after the pressing tongs have been removed, the protective sleeve is connected again with the fitting in the original manner, so that the deformed region of the composite pipe is not visible from the outside, wherein the protective sleeve that is pushed on also protects against bends or kinks. This line connection is very complicated to produce because the connection piece of the fitting must be specially constructed to afford adequate axial securing and sealing of the composite pipe which is pressed thereon. Further, the sealing location is too far away from the front of the connection piece of the fitting to exclude gaps between the outer surface of the connection piece and the inner surface of the pushed on composite pipe.
A different prior art arrangement of a line pipe connection is disclosed in reference DE-GM 74 06 802. This prior art arrangement comprises a coupling ring made of thermoplastic for connecting butt-jointed pipe ends with external reinforcements such as ribs, beads or the like. The coupling ring has a circumferentially extending bead, which engages in the gap between the butt-jointed pipe ends, and annular surfaces whose outer diameter narrows conically toward the ends of the coupling rings. The coupling ring can be inserted into the pipe ends and fastened by gluing, preferably by means of a two-component cement, so as to form a connection through the agency of a bonding substance. This pipe connection has the disadvantage that the pipes to be connected must be provided with external reinforcements in order to ensure the required stiffness of the connection. Further, the coupling ring must be provided with conical ring surfaces to ensure flawless cementing.